To meet the need for miniaturization, electronic packaging technologies have provided solutions permitting increased densities. With a surface-mount technology (“SMT”), electronic components are mounted directly on the surface of a printed circuit board (“PCB”). One type of surface mount technology is a ball grid array (“BGA”) package, which has pads on the bottom of the package with a solder ball initially on each pad. BGA packaging is quite small and typically used for handheld devices, such as smart phones.
Another high-density package is a land grid array (“LGA”) package. An LGA package has a grid of contacts on the underside of the package. An LGA package is used with an LGA socket. One type of LGA socket has a grid of spring-like contacts, each with a landing pad for engagement with a respective metallic pad on the underside of a packaged electronic device. A typical use of an LGA socket is to hold a microprocessor of a desktop computer.
Given the spring-like nature of the grid of contacts in the LGA socket, a downward compressive force is needed to seat the package onto the LGA socket contacts and maintain the package in place. The force varies by the number of contacts the LGA socket has, and a typical range is 100 pounds to 300 pounds. One prior technique to provide the force has been to use an independent loading mechanism (“ILM”), which has a load plate, a load plate hinge, a load plate tongue, a hinge lever, and an active lever. Disadvantages of the ILM are its relatively large size, high cost, and high complexity.
Electronic devices and components are surface mounted on PCBs typically during the assembly and testing processes. In other words, configuration of the components is done at that time of the initial building of the motherboard. As a result, the motherboard contains multiple components that are not easily reconfigured.
Especially in the server segment, complexity is increasing, leading to the need for more devices and components. In particular, additional features and compatibilities are being added to the central processing unit (“CPU”) package. Increasing performance is required from generation to generation. Changes are happening with respect to packaging, including the use of multichip packages. The CPU package power needs are increasing. The speed of the input/output (“I/O”) signal for a CPU package is increasing dramatically. The device complexity of products is increasing due to more components being added to the CPU package.
The increase in product complexity has resulted in an increased need for better configurability. In the prior art, one way configurability was met was through the use of electrical/mechanical sockets. For example, a device in a socket could be later replaced by a different device. In addition, empty sockets could be added at assembly to be used later by additional devices. Typical disadvantages of these approaches, however, include high cost and complex implementation.
Another prior art way of reconfiguring components is through reworking. A typical prior art rework is a finishing operation or repair of components on a PCB, typically involving de-soldering or re-soldering done at a rework station with a heat station. A disadvantage of this approach is that a customer or end user might not have the specialized equipment needed.
The narrow traces and small contacts on typical SMT packages, sockets, and printed circuit boards are not suited for high power, high voltage, or high current.